text: /*-
   *   BSD LICENSE
   *
   *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
   *   All rights reserved.
   *
   *   Redistribution and use in source and binary forms, with or without
   *   modification, are permitted provided that the following conditions
   *   are met:
   *
   *     * Redistributions of source code must retain the above copyright
   *       notice, this list of conditions and the following disclaimer.
   *     * Redistributions in binary form must reproduce the above copyright
   *       notice, this list of conditions and the following disclaimer in
   *       the documentation and/or other materials provided with the
   *       distribution.
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   *       contributors may be used to endorse or promote products derived
   *       from this software without specific prior written permission.
   *
   *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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   *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #ifndef _RTE_IP_FRAG_H_
  #define _RTE_IP_FRAG_H_
  
  /**
   * @file
   * RTE IP Fragmentation and Reassembly
   *
   * Implementation of IP packet fragmentation and reassembly.
   */
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  #include <stdint.h>
  #include <stdio.h>
  
  #include <rte_malloc.h>
  #include <rte_memory.h>
  #include <rte_ip.h>
  #include <rte_byteorder.h>
  
  struct rte_mbuf;
  
  enum {
  	IP_LAST_FRAG_IDX,    /**< index of last fragment */
  	IP_FIRST_FRAG_IDX,   /**< index of first fragment */
  	IP_MIN_FRAG_NUM,     /**< minimum number of fragments */
  	IP_MAX_FRAG_NUM = RTE_LIBRTE_IP_FRAG_MAX_FRAG,
  	/**< maximum number of fragments per packet */
  };
  
  /** @internal fragmented mbuf */
  struct ip_frag {
  	uint16_t ofs;          /**< offset into the packet */
  	uint16_t len;          /**< length of fragment */
  	struct rte_mbuf *mb;   /**< fragment mbuf */
  };
  
  /** @internal <src addr, dst_addr, id> to uniquely indetify fragmented datagram. */
  struct ip_frag_key {
  	uint64_t src_dst[4];      /**< src address, first 8 bytes used for IPv4 */
  	uint32_t id;           /**< dst address */
  	uint32_t key_len;      /**< src/dst key length */
  };
  
  /**
   * @internal Fragmented packet to reassemble.
   * First two entries in the frags[] array are for the last and first fragments.
   */
  struct ip_frag_pkt {
  	TAILQ_ENTRY(ip_frag_pkt) lru;   /**< LRU list */
  	struct ip_frag_key key;           /**< fragmentation key */
  	uint64_t             start;       /**< creation timestamp */
  	uint32_t             total_size;  /**< expected reassembled size */
  	uint32_t             frag_size;   /**< size of fragments received */
  	uint32_t             last_idx;    /**< index of next entry to fill */
  	struct ip_frag       frags[IP_MAX_FRAG_NUM]; /**< fragments */
  } __rte_cache_aligned;
  
  #define IP_FRAG_DEATH_ROW_LEN 32 /**< death row size (in packets) */
  
  /** mbuf death row (packets to be freed) */
  struct rte_ip_frag_death_row {
  	uint32_t cnt;          /**< number of mbufs currently on death row */
  	struct rte_mbuf *row[IP_FRAG_DEATH_ROW_LEN * (IP_MAX_FRAG_NUM + 1)];
  	/**< mbufs to be freed */
  };
  
  TAILQ_HEAD(ip_pkt_list, ip_frag_pkt); /**< @internal fragments tailq */
  
  /** fragmentation table statistics */
  struct ip_frag_tbl_stat {
  	uint64_t find_num;      /**< total # of find/insert attempts. */
  	uint64_t add_num;       /**< # of add ops. */
  	uint64_t del_num;       /**< # of del ops. */
  	uint64_t reuse_num;     /**< # of reuse (del/add) ops. */
  	uint64_t fail_total;    /**< total # of add failures. */
  	uint64_t fail_nospace;  /**< # of 'no space' add failures. */
  } __rte_cache_aligned;
  
  /** fragmentation table */
  struct rte_ip_frag_tbl {
  	uint64_t             max_cycles;      /**< ttl for table entries. */
  	uint32_t             entry_mask;      /**< hash value mask. */
  	uint32_t             max_entries;     /**< max entries allowed. */
  	uint32_t             use_entries;     /**< entries in use. */
  	uint32_t             bucket_entries;  /**< hash assocaitivity. */
  	uint32_t             nb_entries;      /**< total size of the table. */
  	uint32_t             nb_buckets;      /**< num of associativity lines. */
  	struct ip_frag_pkt *last;         /**< last used entry. */
  	struct ip_pkt_list lru;           /**< LRU list for table entries. */
  	struct ip_frag_tbl_stat stat;     /**< statistics counters. */
  	__extension__ struct ip_frag_pkt pkt[0]; /**< hash table. */
  };
  
  /** IPv6 fragment extension header */
  #define	RTE_IPV6_EHDR_MF_SHIFT			0
  #define	RTE_IPV6_EHDR_MF_MASK			1
  #define	RTE_IPV6_EHDR_FO_SHIFT			3
  #define	RTE_IPV6_EHDR_FO_MASK			(~((1 << RTE_IPV6_EHDR_FO_SHIFT) - 1))
  
  #define RTE_IPV6_FRAG_USED_MASK			\
  	(RTE_IPV6_EHDR_MF_MASK | RTE_IPV6_EHDR_FO_MASK)
  
  #define RTE_IPV6_GET_MF(x)				((x) & RTE_IPV6_EHDR_MF_MASK)
  #define RTE_IPV6_GET_FO(x)				((x) >> RTE_IPV6_EHDR_FO_SHIFT)
  
  #define RTE_IPV6_SET_FRAG_DATA(fo, mf)	\
  	(((fo) & RTE_IPV6_EHDR_FO_MASK) | ((mf) & RTE_IPV6_EHDR_MF_MASK))
  
  struct ipv6_extension_fragment {
  	uint8_t next_header;            /**< Next header type */
  	uint8_t reserved;               /**< Reserved */
  	uint16_t frag_data;             /**< All fragmentation data */
  	uint32_t id;                    /**< Packet ID */
  } __attribute__((__packed__));
  
  
  
  /**
   * Create a new IP fragmentation table.
   *
   * @param bucket_num
   *   Number of buckets in the hash table.
   * @param bucket_entries
   *   Number of entries per bucket (e.g. hash associativity).
   *   Should be power of two.
   * @param max_entries
   *   Maximum number of entries that could be stored in the table.
   *   The value should be less or equal then bucket_num * bucket_entries.
   * @param max_cycles
   *   Maximum TTL in cycles for each fragmented packet.
   * @param socket_id
   *   The *socket_id* argument is the socket identifier in the case of
   *   NUMA. The value can be *SOCKET_ID_ANY* if there is no NUMA constraints.
   * @return
   *   The pointer to the new allocated fragmentation table, on success. NULL on error.
   */
  struct rte_ip_frag_tbl * rte_ip_frag_table_create(uint32_t bucket_num,
  		uint32_t bucket_entries,  uint32_t max_entries,
  		uint64_t max_cycles, int socket_id);
  
  /**
   * Free allocated IP fragmentation table.
   *
   * @param tbl
   *   Fragmentation table to free.
   */
  void
  rte_ip_frag_table_destroy(struct rte_ip_frag_tbl *tbl);
  
  /**
   * This function implements the fragmentation of IPv6 packets.
   *
   * @param pkt_in
   *   The input packet.
   * @param pkts_out
   *   Array storing the output fragments.
   * @param nb_pkts_out
   *   Number of fragments.
   * @param mtu_size
   *   Size in bytes of the Maximum Transfer Unit (MTU) for the outgoing IPv6
   *   datagrams. This value includes the size of the IPv6 header.
   * @param pool_direct
   *   MBUF pool used for allocating direct buffers for the output fragments.
   * @param pool_indirect
   *   MBUF pool used for allocating indirect buffers for the output fragments.
   * @return
   *   Upon successful completion - number of output fragments placed
   *   in the pkts_out array.
   *   Otherwise - (-1) * errno.
   */
  int32_t
  rte_ipv6_fragment_packet(struct rte_mbuf *pkt_in,
  		struct rte_mbuf **pkts_out,
  		uint16_t nb_pkts_out,
  		uint16_t mtu_size,
  		struct rte_mempool *pool_direct,
  		struct rte_mempool *pool_indirect);
  
  /**
   * This function implements reassembly of fragmented IPv6 packets.
   * Incoming mbuf should have its l2_len/l3_len fields setup correctly.
   *
   * @param tbl
   *   Table where to lookup/add the fragmented packet.
   * @param dr
   *   Death row to free buffers to
   * @param mb
   *   Incoming mbuf with IPv6 fragment.
   * @param tms
   *   Fragment arrival timestamp.
   * @param ip_hdr
   *   Pointer to the IPv6 header.
   * @param frag_hdr
   *   Pointer to the IPv6 fragment extension header.
   * @return
   *   Pointer to mbuf for reassembled packet, or NULL if:
   *   - an error occurred.
   *   - not all fragments of the packet are collected yet.
   */
  struct rte_mbuf *rte_ipv6_frag_reassemble_packet(struct rte_ip_frag_tbl *tbl,
  		struct rte_ip_frag_death_row *dr,
  		struct rte_mbuf *mb, uint64_t tms, struct ipv6_hdr *ip_hdr,
  		struct ipv6_extension_fragment *frag_hdr);
  
  /**
   * Return a pointer to the packet's fragment header, if found.
   * It only looks at the extension header that's right after the fixed IPv6
   * header, and doesn't follow the whole chain of extension headers.
   *
   * @param hdr
   *   Pointer to the IPv6 header.
   * @return
   *   Pointer to the IPv6 fragment extension header, or NULL if it's not
   *   present.
   */
  static inline struct ipv6_extension_fragment *
  rte_ipv6_frag_get_ipv6_fragment_header(struct ipv6_hdr *hdr)
  {
  	if (hdr->proto == IPPROTO_FRAGMENT) {
  		return (struct ipv6_extension_fragment *) ++hdr;
  	}
  	else
  		return NULL;
  }
  
  /**
   * IPv4 fragmentation.
   *
   * This function implements the fragmentation of IPv4 packets.
   *
   * @param pkt_in
   *   The input packet.
   * @param pkts_out
   *   Array storing the output fragments.
   * @param nb_pkts_out
   *   Number of fragments.
   * @param mtu_size
   *   Size in bytes of the Maximum Transfer Unit (MTU) for the outgoing IPv4
   *   datagrams. This value includes the size of the IPv4 header.
   * @param pool_direct
   *   MBUF pool used for allocating direct buffers for the output fragments.
   * @param pool_indirect
   *   MBUF pool used for allocating indirect buffers for the output fragments.
   * @return
   *   Upon successful completion - number of output fragments placed
   *   in the pkts_out array.
   *   Otherwise - (-1) * errno.
   */
  int32_t rte_ipv4_fragment_packet(struct rte_mbuf *pkt_in,
  			struct rte_mbuf **pkts_out,
  			uint16_t nb_pkts_out, uint16_t mtu_size,
  			struct rte_mempool *pool_direct,
  			struct rte_mempool *pool_indirect);
  
  /**
   * This function implements reassembly of fragmented IPv4 packets.
   * Incoming mbufs should have its l2_len/l3_len fields setup correclty.
   *
   * @param tbl
   *   Table where to lookup/add the fragmented packet.
   * @param dr
   *   Death row to free buffers to
   * @param mb
   *   Incoming mbuf with IPv4 fragment.
   * @param tms
   *   Fragment arrival timestamp.
   * @param ip_hdr
   *   Pointer to the IPV4 header inside the fragment.
   * @return
   *   Pointer to mbuf for reassebled packet, or NULL if:
   *   - an error occurred.
   *   - not all fragments of the packet are collected yet.
   */
  struct rte_mbuf * rte_ipv4_frag_reassemble_packet(struct rte_ip_frag_tbl *tbl,
  		struct rte_ip_frag_death_row *dr,
  		struct rte_mbuf *mb, uint64_t tms, struct ipv4_hdr *ip_hdr);
  
  /**
   * Check if the IPv4 packet is fragmented
   *
   * @param hdr
   *   IPv4 header of the packet
   * @return
   *   1 if fragmented, 0 if not fragmented
   */
  static inline int
  rte_ipv4_frag_pkt_is_fragmented(const struct ipv4_hdr * hdr) {
  	uint16_t flag_offset, ip_flag, ip_ofs;
  
  	flag_offset = rte_be_to_cpu_16(hdr->fragment_offset);
  	ip_ofs = (uint16_t)(flag_offset & IPV4_HDR_OFFSET_MASK);
  	ip_flag = (uint16_t)(flag_offset & IPV4_HDR_MF_FLAG);
  
  	return ip_flag != 0 || ip_ofs  != 0;
  }
  
  /**
   * Free mbufs on a given death row.
   *
   * @param dr
   *   Death row to free mbufs in.
   * @param prefetch
   *   How many buffers to prefetch before freeing.
   */
  void rte_ip_frag_free_death_row(struct rte_ip_frag_death_row *dr,
  		uint32_t prefetch);
  
  
  /**
   * Dump fragmentation table statistics to file.
   *
   * @param f
   *   File to dump statistics to
   * @param tbl
   *   Fragmentation table to dump statistics from
   */
  void
  rte_ip_frag_table_statistics_dump(FILE * f, const struct rte_ip_frag_tbl *tbl);
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif /* _RTE_IP_FRAG_H_ */
  